diff --git a/docs/releasenotes/version17.md b/docs/releasenotes/version17.md index e020fe68..d14d347e 100644 --- a/docs/releasenotes/version17.md +++ b/docs/releasenotes/version17.md @@ -3,6 +3,22 @@ # v17 +## v17.6.0 + +- Fixed a regression in OCR quality for PDFs that paint a 1-bit image mask + (stencil) with a gray or colored fill color. Previously such pages were + rasterized as 1-bit black-and-white before OCR, so Ghostscript dithered + mid-tone text into an unreadable stipple and Tesseract failed to recognize + it. The rasterizer now inspects the fill color used to paint a mask and + promotes the page to grayscale or full color as needed, so the distinction + is preserved for the OCR engine. This applies to both the Ghostscript and + pypdfium rasterizers. {issue}`1688` +- The default 1-bit raster device for Ghostscript is now ``pngmonod`` + (error-diffusion) instead of ``pngmono`` (ordered dithering). It produces + better input for OCR on faint or anti-aliased scans at negligible cost and + no change to output file size, since the rasterized image is an + intermediate that is discarded after OCR. + ## v17.5.0 - Added support for the ``end`` alias in ``--pages``, denoting the last page